U.S. patent application number 17/574813 was filed with the patent office on 2022-08-04 for refrigerant compressor having dedicated inlets for stator and rotor cooling lines.
The applicant listed for this patent is DANFOSS A/S. Invention is credited to Jin Yan, Tianli Zhang.
Application Number | 20220243965 17/574813 |
Document ID | / |
Family ID | 1000006137380 |
Filed Date | 2022-08-04 |
United States Patent
Application |
20220243965 |
Kind Code |
A1 |
Zhang; Tianli ; et
al. |
August 4, 2022 |
REFRIGERANT COMPRESSOR HAVING DEDICATED INLETS FOR STATOR AND ROTOR
COOLING LINES
Abstract
In some aspects, the techniques described herein relate to a
refrigerant compressor, including: an impeller; a shaft; a motor
configured to rotate the impeller via the shaft, wherein the motor
includes a stator and a rotor; and a housing surrounding the motor,
wherein the housing includes a first inlet configured to permit
fluid to enter the housing and flow along a stator cooling line and
a second inlet configured to permit fluid to enter the housing and
flow a rotor cooling line, and wherein the first inlet is separate
from the second inlet.
Inventors: |
Zhang; Tianli; (Ann Arbor,
MI) ; Yan; Jin; (Tallahassee, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DANFOSS A/S |
NORDBORG |
|
DK |
|
|
Family ID: |
1000006137380 |
Appl. No.: |
17/574813 |
Filed: |
January 13, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
63145009 |
Feb 3, 2021 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02K 9/06 20130101; F04D
25/06 20130101; F25B 31/026 20130101; H02K 5/207 20210101; H02K
1/30 20130101 |
International
Class: |
F25B 31/02 20060101
F25B031/02; F04D 25/06 20060101 F04D025/06; H02K 1/30 20060101
H02K001/30; H02K 5/20 20060101 H02K005/20; H02K 9/06 20060101
H02K009/06 |
Claims
1. A refrigerant compressor, comprising: an impeller; a shaft; a
motor configured to rotate the impeller via the shaft, wherein the
motor includes a stator and a rotor; and a housing surrounding the
motor, wherein the housing includes a first inlet configured to
permit fluid to enter the housing and flow along a stator cooling
line and a second inlet configured to permit fluid to enter the
housing and flow a rotor cooling line, and wherein the first inlet
is separate from the second inlet.
2. The refrigerant compressor as recited in claim 1, wherein the
rotor is directly mounted to the shaft and is configured to rotate
with the shaft.
3. The refrigerant compressor as recited in claim 2, wherein the
rotor is provided by magnetic material.
4. The refrigerant compressor as recited in claim 3, wherein the
shaft includes a non-magnetic portion.
5. The refrigerant compressor as recited in claim 3, further
comprising: a sleeve connecting the rotor to the shaft, wherein the
sleeve radially surrounds the rotor.
6. The refrigerant compressor as recited in claim 5, wherein the
shaft includes a radial recess, and the sleeve is arranged in the
recess such that the sleeve is radially flush with the shaft.
7. The refrigerant compressor as recited in claim 5, wherein the
sleeve is arranged such that a radial gap exists radially between
the sleeve and an inner surface of the stator.
8. The refrigerant compressor as recited in claim 7, wherein the
radial gap extends along the entire axial length of the rotor.
9. The refrigerant compressor as recited in claim 1, wherein the
housing includes a main portion extending generally from a first
location adjacent the impeller to a second location on an opposite
side of the motor as the impeller, an end cap adjacent the second
location and enclosing a first end of the main portion, and a wall
adjacent the first location and providing a boundary between the
motor and the impeller.
10. The refrigerant compressor as recited in claim 9, wherein the
main portion includes both the first inlet and the second
inlet.
11. The refrigerant compressor as recited in claim 10, wherein the
end cap includes an outlet, and wherein the refrigerant compressor
is configured such that fluid flowing along both the stator and
rotor cooling lines exits the refrigerant compressor via the
outlet.
12. The refrigerant compressor as recited in claim 11, wherein the
refrigerant compressor is configured such that fluid flowing along
the stator cooling line intermixes with fluid flowing along the
rotor cooling line at a location upstream of the end cap and
downstream of the motor.
13. The refrigerant compressor as recited in claim 9, wherein the
refrigerant compressor is configured such that: the fluid flowing
along the rotor cooling line is not provided by leakage flow
between the shaft and the wall, the fluid flowing along the rotor
cooling line is not provided by flow that has exited the stator
cooling line, and the fluid flowing along the stator cooling line
is not provided by fluid that has exited the rotor cooling
line.
14. A refrigerant system, comprising: a main refrigerant loop
including a compressor, a condenser, an evaporator, and an
expansion device, wherein the compressor includes: an impeller; a
shaft; a motor configured to rotate the impeller via the shaft,
wherein the motor includes a stator and a rotor; and a housing
surrounding the motor, wherein the housing includes a first inlet
configured to permit fluid to enter the housing and flow along a
stator cooling line and a second inlet configured to permit fluid
to enter the housing and flow a rotor cooling line, and wherein the
first inlet is separate from the second inlet.
15. The refrigerant system as recited in claim 14, wherein: the
rotor is directly mounted to the shaft and is configured to rotate
with the shaft, the rotor is provided by magnetic material, the
compressor further comprises a sleeve connecting the rotor to the
shaft, and the sleeve radially surrounds the rotor.
16. The refrigerant system as recited in claim 15, wherein the
shaft includes a radial recess, and the sleeve is arranged in the
recess such that the sleeve is radially flush with the shaft.
17. The refrigerant system as recited in claim 16, wherein the
sleeve is arranged such that a radial gap exists radially between
the sleeve and an inner surface of the stator.
18. The refrigerant system as recited in claim 17, wherein the
radial gap extends along the entire axial length of the rotor.
19. The refrigerant system as recited in claim 14, wherein: the
housing includes a main portion extending generally from a first
location adjacent the impeller to a second location on an opposite
side of the motor as the impeller, an end cap adjacent the second
location and enclosing a first end of the main portion, and a wall
adjacent the first location and providing a boundary between the
motor and the impeller, the main portion includes both the first
inlet and the second inlet, the end cap includes an outlet, and the
refrigerant compressor is configured such that fluid flowing along
both the stator and rotor cooling lines exits the refrigerant
compressor via the outlet.
20. The refrigerant system as recited in claim 19, wherein the
compressor is configured such that: the fluid flowing along the
rotor cooling line is not provided by leakage flow between the
shaft and the wall, the fluid flowing along the rotor cooling line
is not provided by flow that has exited the stator cooling line,
and the fluid flowing along the stator cooling line is not provided
by fluid that has exited the rotor cooling line.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 63/145,009, filed Feb. 3, 2021, the entirety of
which is herein incorporated by reference.
BACKGROUND
[0002] Refrigerant compressors are used to circulate refrigerant in
a chiller via a refrigerant loop. Refrigerant loops are known to
include a condenser, an expansion device, and an evaporator. The
compressor compresses the refrigerant, which then travels to a
condenser, which in turn cools and condenses the refrigerant. The
refrigerant then goes to an expansion device, which decreases the
pressure of the fluid, and to the evaporator, where the refrigerant
is vaporized, completing a refrigeration cycle.
[0003] Many refrigerant compressors are centrifugal compressors and
have an electric motor that drives at least one impeller to
pressurize refrigerant. The at least one impeller is mounted to a
rotatable shaft. The motor in some examples is an electric motor
including a rotor and a stator.
SUMMARY
[0004] In some aspects, the techniques described herein relate to a
refrigerant compressor, including: an impeller; a shaft; a motor
configured to rotate the impeller via the shaft, wherein the motor
includes a stator and a rotor; and a housing surrounding the motor,
wherein the housing includes a first inlet configured to permit
fluid to enter the housing and flow along a stator cooling line and
a second inlet configured to permit fluid to enter the housing and
flow a rotor cooling line, and wherein the first inlet is separate
from the second inlet.
[0005] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the rotor is directly mounted to
the shaft and is configured to rotate with the shaft.
[0006] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the rotor is provided by magnetic
material.
[0007] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the shaft includes a non-magnetic
portion.
[0008] In some aspects, the techniques described herein relate to a
refrigerant compressor, further including: a sleeve connecting the
rotor to the shaft, wherein the sleeve radially surrounds the
rotor.
[0009] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the shaft includes a radial recess,
and the sleeve is arranged in the recess such that the sleeve is
radially flush with the shaft.
[0010] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the sleeve is arranged such that a
radial gap exists radially between the sleeve and an inner surface
of the stator.
[0011] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the radial gap extends along the
entire axial length of the rotor.
[0012] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the housing includes a main portion
extending generally from a first location adjacent the impeller to
a second location on an opposite side of the motor as the impeller,
an end cap adjacent the second location and enclosing a first end
of the main portion, and a wall adjacent the first location and
providing a boundary between the motor and the impeller.
[0013] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the main portion includes both the
first inlet and the second inlet.
[0014] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the end cap includes an outlet, and
wherein the refrigerant compressor is configured such that fluid
flowing along both the stator and rotor cooling lines exits the
refrigerant compressor via the outlet.
[0015] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the refrigerant compressor is
configured such that fluid flowing along the stator cooling line
intermixes with fluid flowing along the rotor cooling line at a
location upstream of the end cap and downstream of the motor.
[0016] In some aspects, the techniques described herein relate to a
refrigerant compressor, wherein the refrigerant compressor is
configured such that: the fluid flowing along the rotor cooling
line is not provided by leakage flow between the shaft and the
wall, the fluid flowing along the rotor cooling line is not
provided by flow that has exited the stator cooling line, and the
fluid flowing along the stator cooling line is not provided by
fluid that has exited the rotor cooling line.
[0017] In some aspects, the techniques described herein relate to a
refrigerant system, including: a main refrigerant loop including a
compressor, a condenser, an evaporator, and an expansion device,
wherein the compressor includes: an impeller; a shaft; a motor
configured to rotate the impeller via the shaft, wherein the motor
includes a stator and a rotor; and a housing surrounding the motor,
wherein the housing includes a first inlet configured to permit
fluid to enter the housing and flow along a stator cooling line and
a second inlet configured to permit fluid to enter the housing and
flow a rotor cooling line, and wherein the first inlet is separate
from the second inlet.
[0018] In some aspects, the techniques described herein relate to a
refrigerant system, wherein: the rotor is directly mounted to the
shaft and is configured to rotate with the shaft, the rotor is
provided by magnetic material, the compressor further includes a
sleeve connecting the rotor to the shaft, and the sleeve radially
surrounds the rotor.
[0019] In some aspects, the techniques described herein relate to a
refrigerant system, wherein the shaft includes a radial recess, and
the sleeve is arranged in the recess such that the sleeve is
radially flush with the shaft.
[0020] In some aspects, the techniques described herein relate to a
refrigerant system, wherein the sleeve is arranged such that a
radial gap exists radially between the sleeve and an inner surface
of the stator.
[0021] In some aspects, the techniques described herein relate to a
refrigerant system, wherein the radial gap extends along the entire
axial length of the rotor.
[0022] In some aspects, the techniques described herein relate to a
refrigerant system, wherein: the housing includes a main portion
extending generally from a first location adjacent the impeller to
a second location on an opposite side of the motor as the impeller,
an end cap adjacent the second location and enclosing a first end
of the main portion, and a wall adjacent the first location and
providing a boundary between the motor and the impeller, the main
portion includes both the first inlet and the second inlet, the end
cap includes an outlet, and the refrigerant compressor is
configured such that fluid flowing along both the stator and rotor
cooling lines exits the refrigerant compressor via the outlet.
[0023] In some aspects, the techniques described herein relate to a
refrigerant system, wherein the compressor is configured such that:
the fluid flowing along the rotor cooling line is not provided by
leakage flow between the shaft and the wall, the fluid flowing
along the rotor cooling line is not provided by flow that has
exited the stator cooling line, and the fluid flowing along the
stator cooling line is not provided by fluid that has exited the
rotor cooling line.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 schematically illustrates an example refrigerant
system.
[0025] FIG. 2 illustrates additional detail of a compressor.
[0026] FIG. 3 is a close-up view of a stator, a rotor, and a rotor
sleeve.
DETAILED DESCRIPTION
[0027] FIG. 1 illustrates a refrigerant system 10. The refrigerant
system 10 includes a main refrigerant loop, or circuit, 12 in
communication with a compressor 14, a condenser 16, an evaporator
18, and an expansion device 20. This refrigerant system 10 may be
used in a chiller, for example. In that example, a cooling tower
may be in fluid communication with the condenser 16. While a
particular example of the refrigerant system 10 is shown, this
application extends to other refrigerant system configurations,
including configurations that do not include a chiller. For
instance, the main refrigerant loop 12 can include an economizer
downstream of the condenser 16 and upstream of the expansion device
20.
[0028] FIG. 2 illustrates an example refrigerant compressor 14
according to this disclosure. The compressor 14 includes an
electric motor 30 including a stator 32 arranged radially outside a
rotor 34.
[0029] The rotor 34 is connected to a shaft 36, which rotates to
drive a compression stage 38. The compression stage 38 includes an
impeller 40 mounted on the shaft 36 and rotatable about an axis A
to compress refrigerant. The shaft 36 may be rotatably supported by
a number of bearing assemblies, such as magnetic bearings.
[0030] The rotor 34 may be directly mounted to the shaft 36, as
shown in FIG. 3. The rotor 34, in this example, is made of magnetic
material and is rotatable in response a magnetic field of the
stator 32. In particular, the rotor 34 is made of a permanent
magnet. The rotor 34 is configured to rotate with the shaft 36 and
the compression stage 38.
[0031] In one example of this disclosure, the rotor 34 is provided
by magnetic material which is attached to the remainder of the
shaft 36, which may be non-magnetic. In this example, a sleeve 42
is configured to connect and attach the rotor 34 to the remainder
of the shaft 36.
[0032] In FIG. 3, the sleeve 42 is radially outward of and radially
surrounds the rotor 34 about the entire circumference of the rotor
34. The sleeve 42 may be considered part of the rotor 34 and/or a
part of the shaft 36, and may be referred to as a rotor sleeve. In
this regard, the rotor 34 and sleeve 42 may together be considered
a rotor or rotor assembly. In one example, the shaft 36 includes a
radial recess, and the sleeve 42 rests in the recess and is
radially flush with the remainder of the shaft 36. In another
example, the sleeve 42 may project radially outward of the
remainder of the shaft 36. In either case, a radial gap 44 exists
radially between the sleeve 42 and an inner surface of the stator
32. The radial gap 44 extends along the entire axial length of the
rotor 34.
[0033] With reference back to FIG. 2, the compressor 14 in this
example includes a housing 46, a portion of which surrounds and
encloses the motor 30. In particular, the housing 46 in FIG. 2
includes a plurality of pieces. A main portion 48 of the housing 46
extends from a point adjacent the compression stage 38 to an
opposite side of the motor 30. An end cap 50 encloses the main
portion 48 at one end. A wall 52 attached to an opposite end of the
main portion 48 as the end cap 50 provides a boundary between the
motor 30 and the compression stage 38. The shaft 36 projects
through the wall 52 to connect to the impeller 40.
[0034] The motor 30 is cooled by refrigerant. In this example, the
motor 30 is cooled by the same refrigerant that is pressurized in
the compression stage 38. An example refrigerant is R-1233ZD, which
is a relatively low-density refrigerant.
[0035] In this example, the motor 30 is cooled by stator cooling
lines 54 and rotor cooling lines 56. The stator and rotor cooling
lines 54, 56 are passageways within the motor 30 and are
represented by the relatively thick lines in FIG. 2. The stator and
rotor cooling lines 54, 56 are mostly independent of one another,
except at locations downstream of the motor 30, as discussed below.
Fluid F.sub.1, which is refrigerant such as R-1233ZD, is
representative of fluid flowing along the stator cooling line 54,
and fluid F.sub.2 is representative of fluid flowing along the
rotor cooling line 56. The fluid F.sub.1, F.sub.2 is sourced from
the main refrigerant loop 12, such as from adjacent an economizer,
in an example.
[0036] The main portion 48 includes separate, dedicated inlets for
the stator and rotor cooling lines 54, 56, in this example. In
particular, with reference to the stator cooling line 54, the fluid
F.sub.1 enters the main portion 48 via an inlet 58. Downstream of
the inlet 58, the fluid F.sub.1 proceeds to circulate about the
stator 32 by way of a circumferential passageway 60. In one
example, an outer radial boundary of the circumferential passageway
60 is provided in part by a helical channel formed in an inner wall
of the main portion 48. In this example, an outer surface of the
stator 32 provides an inner radial boundary for the circumferential
passageway 60. Downstream of the stator 32, the fluid F.sub.1 flows
toward the end cap 50 and exits the housing 46 via an outlet 62
formed in the end cap 50.
[0037] With reference to the rotor cooling line 56, the fluid
F.sub.2 enters the main portion 48 via an inlet 64. The inlet 64 is
separate from the inlet 58. Further, the inlet 64 is axially
between the motor 30 and the compression stage 38, in this example.
As such, fluid F.sub.2 flowing into the inlet 64 can enter into and
flow along the radial gap 44. Downstream of the radial gap 44, the
fluid F.sub.2 flows toward the end cap 50 and exits the housing 46
via the outlet 62.
[0038] Fluids F.sub.1, F.sub.2 may intermix upstream of the end cap
50 and downstream of the motor 30. Thus, the fluids F.sub.1,
F.sub.2 exit the housing 46 via a common outlet 62. Downstream of
the outlet 62, the fluids F.sub.1, F.sub.2 are returned to the main
refrigerant loop 12.
[0039] The fluid F.sub.2 is not provided by leakage flow between
the shaft 36 and the wall 52. Nor is the fluid F.sub.2 provided by
flow that has already been circulated relative to the stator 32.
Further, the fluid F.sub.1 is not provided by fluid that has
already been circulated relative to the rotor 34. In this way, the
fluids F.sub.1, F.sub.2 flowing along the stator and rotor cooling
lines 54, 56 are able to effectively absorb heat from the stator 32
and rotor 34, respectively.
[0040] Further, since the fluids F.sub.1, F.sub.2 are provided from
separate, dedicated inlets and flow along a separate flow paths,
that is until the fluids F.sub.1, F.sub.2 are downstream of the
motor 30, the fluids F.sub.1, F.sub.2 exhibit a decreased pressure
drop between their respective inlets and outlets, and thus the
fluids F.sub.1, F.sub.2 can exhibit a greater flow rate compared to
prior motor cooling fluids. The greater flow rate also leads to
more effective heat transfer.
[0041] It should be understood that terms such as "axial,"
"radial," and "circumferential" are used above with reference to
the normal operational attitude of an electric machine. Further,
these terms have been used herein for purposes of explanation, and
should not be considered otherwise limiting. Terms such
"generally," "about," and "substantially" are not intended to be
boundaryless terms, and should be interpreted consistent with the
way one skilled in the art would interpret those terms.
[0042] Although the different examples have the specific components
shown in the illustrations, embodiments of this disclosure are not
limited to those particular combinations. It is possible to use
some of the components or features from one of the examples in
combination with features or components from another one of the
examples. In addition, the various figures accompanying this
disclosure are not necessarily to scale, and some features may be
exaggerated or minimized to show certain details of a particular
component or arrangement.
[0043] One of ordinary skill in this art would understand that the
above-described embodiments are exemplary and non-limiting. That
is, modifications of this disclosure would come within the scope of
the claims. Accordingly, the following claims should be studied to
determine their true scope and content.
* * * * *